From 65aa6a56d1eabbdfaf1d26281eb290d4178f15ef Mon Sep 17 00:00:00 2001
From: Matthias Kruk <m@m10k.eu>
Date: Sun, 21 Mar 2021 08:23:32 +0900
Subject: [PATCH] toolbox: Implement toolbox initialization and module loading

When writing shell scripts, I often find myself copying or rewriting
functions because bash does not provide a mechanism to easily reuse
code. This commit adds a mechanism for loadable bash "modules".
---
 toolbox.sh | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 toolbox.sh

diff --git a/toolbox.sh b/toolbox.sh
new file mode 100644
index 0000000..9f419c4
--- /dev/null
+++ b/toolbox.sh
@@ -0,0 +1,78 @@
+#!/bin/bash
+
+#
+# Toolbox - A set of unsophisticated bash "modules"
+# Copyright (C) 2021 - Matthias Kruk <m@m10k.eu>
+#
+
+__toolbox_init() {
+	export TOOLBOX_PATH="$(dirname "$(realpath "${BASH_SOURCE[0]}")")"
+	export TOOLBOX_HOME="$HOME/.toolbox"
+
+	declare -ag __TOOLBOX_INCLUDED=()
+
+	return 0
+}
+
+have() {
+	local module
+	local included
+
+	module="$1"
+
+	for included in "${__TOOLBOX_INCLUDED[@]}"; do
+		local modpath
+
+		modpath="$TOOLBOX_PATH/include/$module.sh"
+
+		if [[ "$included" == "$modpath" ]]; then
+			return 0
+		fi
+	done
+
+	return 1
+}
+
+include() {
+	local err
+	local module
+
+	err=0
+
+	for module in "$@"; do
+		local modpath
+
+		if have "$module"; then
+			continue
+		fi
+
+		modpath="$TOOLBOX_PATH/include/$module.sh"
+
+		if ! . "$modpath"; then
+			echo "ERROR: Could not load $modpath" 1>&2
+			err=1
+			continue
+		fi
+
+		if ! __init; then
+			echo "ERROR: Could not initialize $module" 1>&2
+			err=1
+		else
+			__TOOLBOX_INCLUDED+=("$modpath")
+		fi
+
+		unset -f __init
+	done
+
+	return "$err"
+}
+
+{
+	if ! compgen -v | grep "^__TOOLBOX_INCLUDED$" &> /dev/null; then
+		if ! __toolbox_init; then
+			echo "Could not initialize toolbox" 1>&2
+		fi
+
+		unset -f __toolbox_init
+	fi
+}
-- 
2.47.3